Phase II single arm, open label, nonrandomized study. The aim of our study is to assess the Progression Free Survival (PFS) in suboptimally cytoreduced epithelial ovarian/ primary peritoneal/ fallopian tube cancer patients treated with the novel combination of carboplatin every 21 days (triweekly) /weekly paclitaxel IV with pembrolizumab IV followed by maintenance pembrolizumab IV.